程序包 cn.taketoday.bytecode

类 ClassReader

java.lang.Object
cn.taketoday.bytecode.ClassReader
public class ClassReader extends Object
A parser to make a ClassVisitor visit a ClassFile structure, as defined in the Java Virtual Machine Specification (JVMS). This class parses the ClassFile content and calls the appropriate visit methods of a given ClassVisitor for each field, method and bytecode instruction encountered.
作者:
Eric Bruneton, Eugene Kuleshov
另请参阅:

  • 字段概要

    字段
    修饰符和类型
    字段
    说明
    private final int[]
    bootstrapMethodOffsets
    The start offsets in classFileBuffer of each element of the bootstrap_methods array (in the BootstrapMethods attribute).
    (专用程序包) final byte[]
    classFileBuffer
    A byte array containing the JVMS ClassFile structure to be parsed.
    private final ConstantDynamic[]
    constantDynamicValues
    The ConstantDynamic objects corresponding to the CONSTANT_Dynamic constant pool items.
    private final String[]
    constantUtf8Values
    The String objects corresponding to the CONSTANT_Utf8 constant pool items.
    private final int[]
    cpInfoOffsets
    The offset in bytes, in classFileBuffer, of each cp_info entry of the ClassFile's constant_pool array, plus one.
    (专用程序包) static final int
    EXPAND_ASM_INSNS
    A flag to expand the ASM specific instructions into an equivalent sequence of standard bytecode instructions.
    static final int
    EXPAND_FRAMES
    A flag to expand the stack map frames.
    final int
    header
    The offset in bytes of the ClassFile's access_flags field.
    private static final int
    INPUT_STREAM_DATA_CHUNK_SIZE
    The size of the temporary byte array used to read class input streams chunk by chunk.
    private static final int
    MAX_BUFFER_SIZE
    The maximum size of array to allocate.
    private final int
    maxStringLength
    A conservative estimate of the maximum length of the strings contained in the constant pool of the class.
    static final int
    SKIP_CODE
    A flag to skip the Code attributes.
    static final int
    SKIP_DEBUG
    A flag to skip the SourceFile, SourceDebugExtension, LocalVariableTable, LocalVariableTypeTable, LineNumberTable and MethodParameters attributes.
    static final int
    SKIP_FRAMES
    A flag to skip the StackMap and StackMapTable attributes.

  • 构造器概要

    构造器
    构造器
    说明
    ClassReader(byte[] classFile)
    Constructs a new ClassReader object.
    ClassReader(byte[] classFileBuffer, int classFileOffset, boolean checkClassVersion)
    Constructs a new ClassReader object.
    ClassReader(byte[] classFileBuffer, int classFileOffset, int classFileLength)
    Constructs a new ClassReader object.
    ClassReader(InputStream inputStream)
    Constructs a new ClassReader object.
    ClassReader(String className)
    Constructs a new ClassReader object.

  • 方法概要

    修饰符和类型
    方法
    说明
    void
    accept(ClassVisitor classVisitor, int parsingOptions)
    Makes the given visitor visit the JVMS ClassFile structure passed to the constructor of this ClassReader.
    void
    accept(ClassVisitor classVisitor, Attribute[] attributePrototypes, int parsingOptions)
    Makes the given visitor visit the JVMS ClassFile structure passed to the constructor of this ClassReader.
    private static int
    calculateBufferSize(InputStream inputStream)
     
    private void
    computeImplicitFrame(Context context)
    Computes the implicit frame of the method currently being parsed (as defined in the given Context) and stores it in the given context.
    private void
    createDebugLabel(int bytecodeOffset, Label[] labels)
    Creates a label with the Label.FLAG_DEBUG_ONLY flag set, if there is no already existing label for the given bytecode offset (otherwise does nothing).
    private Label
    createLabel(int bytecodeOffset, Label[] labels)
    Creates a label without the Label.FLAG_DEBUG_ONLY flag set, for the given bytecode offset.
    int
    getAccess()
    Returns the class's access flags (see Opcodes).
    String
    getClassName()
    Returns the internal name of the class (see Type.getInternalName()).
    (专用程序包) final int
    getFirstAttributeOffset()
    Returns the offset in classFileBuffer of the first ClassFile's 'attributes' array field entry.
    String[]
    getInterfaces()
    Returns the internal names of the implemented interfaces (see Type.getInternalName()).
    int
    getItem(int constantPoolEntryIndex)
    Returns the start offset in this ClassReader of a JVMS 'cp_info' structure (i.e. a constant pool entry), plus one.
    int
    getItemCount()
    Returns the number of entries in the class's constant pool table.
    int
    getMaxStringLength()
    Returns a conservative estimate of the maximum length of the strings contained in the class's constant pool table.
    String
    getSuperName()
    Returns the internal of name of the super class (see Type.getInternalName()).
    private int
    getTypeAnnotationBytecodeOffset(int[] typeAnnotationOffsets, int typeAnnotationIndex)
    Returns the bytecode offset corresponding to the specified JVMS 'type_annotation' structure, or -1 if there is no such type_annotation of if it does not have a bytecode offset.
    private Attribute
    readAttribute(Attribute[] attributePrototypes, String type, int offset, int length, char[] charBuffer, int codeAttributeOffset, Label[] labels)
    Reads a non standard JVMS 'attribute' structure in classFileBuffer.
    private int[]
    readBootstrapMethodsAttribute(int maxStringLength)
    Reads the BootstrapMethods attribute to compute the offset of each bootstrap method.
    int
    readByte(int offset)
    Reads a byte value in this ClassReader.
    String
    readClass(int offset, char[] charBuffer)
    Reads a CONSTANT_Class constant pool entry in this ClassReader.
    private void
    readCode(MethodVisitor methodVisitor, Context context, int codeOffset)
    Reads a JVMS 'Code' attribute and makes the given visitor visit it.
    Object
    readConst(int constantPoolEntryIndex, char[] charBuffer)
    Reads a numeric or string constant pool entry in this ClassReader.
    private ConstantDynamic
    readConstantDynamic(int constantPoolEntryIndex, char[] charBuffer)
    Reads a CONSTANT_Dynamic constant pool entry in classFileBuffer.
    private int
    readElementValue(AnnotationVisitor annotationVisitor, int elementValueOffset, String elementName, char[] charBuffer)
    Reads a JVMS 'element_value' structure and makes the given visitor visit it.
    private int
    readElementValues(AnnotationVisitor annotationVisitor, int annotationOffset, boolean named, char[] charBuffer)
    Reads the element values of a JVMS 'annotation' structure and makes the given visitor visit them.
    private int
    readField(ClassVisitor classVisitor, Context context, int fieldInfoOffset)
    Reads a JVMS field_info structure and makes the given visitor visit it.
    int
    readInt(int offset)
    Reads a signed int value in this ClassReader.
    protected Label
    readLabel(int bytecodeOffset, Label[] labels)
    Returns the label corresponding to the given bytecode offset.
    long
    readLong(int offset)
    Reads a signed long value in this ClassReader.
    private int
    readMethod(ClassVisitor classVisitor, Context context, int methodInfoOffset)
    Reads a JVMS method_info structure and makes the given visitor visit it.
    String
    readModule(int offset, char[] charBuffer)
    Reads a CONSTANT_Module constant pool entry in this ClassReader.
    private void
    readModuleAttributes(ClassVisitor classVisitor, Context context, int moduleOffset, int modulePackagesOffset, String moduleMainClass)
    Reads the Module, ModulePackages and ModuleMainClass attributes and visit them.
    String
    readPackage(int offset, char[] charBuffer)
    Reads a CONSTANT_Package constant pool entry in this ClassReader.
    private void
    readParameterAnnotations(MethodVisitor methodVisitor, Context context, int runtimeParameterAnnotationsOffset, boolean visible)
    Reads a Runtime[In]VisibleParameterAnnotations attribute and makes the given visitor visit it.
    private int
    readRecordComponent(ClassVisitor classVisitor, Context context, int recordComponentOffset)
    Reads a record component and visit it.
    short
    readShort(int offset)
    Reads a signed short value in this ClassReader.
    private int
    readStackMapFrame(int stackMapFrameOffset, boolean compressed, boolean expand, Context context)
    Reads a JVMS 'stack_map_frame' structure and stores the result in the given Context object.
    private static byte[]
    readStream(InputStream inputStream, boolean close)
    Reads the given input stream and returns its content as a byte array.
    private String
    readStringish(int offset, char[] charBuffer)
    Reads a CONSTANT_Class, CONSTANT_String, CONSTANT_MethodType, CONSTANT_Module or CONSTANT_Package constant pool entry in classFileBuffer.
    private int[]
    readTypeAnnotations(MethodVisitor methodVisitor, Context context, int runtimeTypeAnnotationsOffset, boolean visible)
    Parses a Runtime[In]VisibleTypeAnnotations attribute to find the offset of each type_annotation entry it contains, to find the corresponding labels, and to visit the try catch block annotations.
    private int
    readTypeAnnotationTarget(Context context, int typeAnnotationOffset)
    Parses the header of a JVMS type_annotation structure to extract its target_type, target_info and target_path (the result is stored in the given context), and returns the start offset of the rest of the type_annotation structure.
    int
    readUnsignedShort(int offset)
    Reads an unsigned short value in this ClassReader.
    (专用程序包) final String
    readUtf(int constantPoolEntryIndex, char[] charBuffer)
    Reads a CONSTANT_Utf8 constant pool entry in classFileBuffer.
    private String
    readUtf(int utfOffset, int utfLength, char[] charBuffer)
    Reads an UTF8 string in classFileBuffer.
    String
    readUTF8(int offset, char[] charBuffer)
    Reads a CONSTANT_Utf8 constant pool entry in this ClassReader.
    private int
    readVerificationTypeInfo(int verificationTypeInfoOffset, Object[] frame, int index, char[] charBuffer, Label[] labels)
    Reads a JVMS 'verification_type_info' structure and stores it at the given index in the given array.

    从类继承的方法 java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • 字段详细资料

    • SKIP_CODE

      public static final int SKIP_CODE
      A flag to skip the Code attributes. If this flag is set the Code attributes are neither parsed nor visited.
      另请参阅:

    • SKIP_DEBUG

      public static final int SKIP_DEBUG
      A flag to skip the SourceFile, SourceDebugExtension, LocalVariableTable, LocalVariableTypeTable, LineNumberTable and MethodParameters attributes. If this flag is set these attributes are neither parsed nor visited (i.e. ClassVisitor.visitSource(java.lang.String, java.lang.String), MethodVisitor.visitLocalVariable(java.lang.String, java.lang.String, java.lang.String, cn.taketoday.bytecode.Label, cn.taketoday.bytecode.Label, int), MethodVisitor.visitLineNumber(int, cn.taketoday.bytecode.Label) and MethodVisitor.visitParameter(java.lang.String, int) are not called).
      另请参阅:

    • SKIP_FRAMES

      public static final int SKIP_FRAMES
      A flag to skip the StackMap and StackMapTable attributes. If this flag is set these attributes are neither parsed nor visited (i.e. MethodVisitor.visitFrame(int, int, java.lang.Object[], int, java.lang.Object[]) is not called). This flag is useful when the ClassWriter.COMPUTE_FRAMES option is used: it avoids visiting frames that will be ignored and recomputed from scratch.
      另请参阅:

    • EXPAND_FRAMES

      public static final int EXPAND_FRAMES
      A flag to expand the stack map frames. By default stack map frames are visited in their original format (i.e. "expanded" for classes whose version is less than V1_6, and "compressed" for the other classes). If this flag is set, stack map frames are always visited in expanded format (this option adds a decompression/compression step in ClassReader and ClassWriter which degrades performance quite a lot).
      另请参阅:

    • EXPAND_ASM_INSNS

      static final int EXPAND_ASM_INSNS
      A flag to expand the ASM specific instructions into an equivalent sequence of standard bytecode instructions. When resolving a forward jump it may happen that the signed 2 bytes offset reserved for it is not sufficient to store the bytecode offset. In this case the jump instruction is replaced with a temporary ASM specific instruction using an unsigned 2 bytes offset (see Label.resolve(byte[], int)). This internal flag is used to re-read classes containing such instructions, in order to replace them with standard instructions. In addition, when this flag is used, goto_w and jsr_w are not converted into goto and jsr, to make sure that infinite loops where a goto_w is replaced with a goto in ClassReader and converted back to a goto_w in ClassWriter cannot occur.
      另请参阅:

    • MAX_BUFFER_SIZE

      private static final int MAX_BUFFER_SIZE
      The maximum size of array to allocate.
      另请参阅:

    • INPUT_STREAM_DATA_CHUNK_SIZE

      private static final int INPUT_STREAM_DATA_CHUNK_SIZE
      The size of the temporary byte array used to read class input streams chunk by chunk.
      另请参阅:

    • classFileBuffer

      final byte[] classFileBuffer
      A byte array containing the JVMS ClassFile structure to be parsed. The content of this array must not be modified. This field is intended for Attribute sub classes, and is normally not needed by class visitors.

      NOTE: the ClassFile structure can start at any offset within this array, i.e. it does not necessarily start at offset 0. Use getItem(int) and header to get correct ClassFile element offsets within this byte array.

    • cpInfoOffsets

      private final int[] cpInfoOffsets
      The offset in bytes, in classFileBuffer, of each cp_info entry of the ClassFile's constant_pool array, plus one. In other words, the offset of constant pool entry i is given by cpInfoOffsets[i] - 1, i.e. its cp_info's tag field is given by b[cpInfoOffsets[i] - 1].

    • constantUtf8Values

      private final String[] constantUtf8Values
      The String objects corresponding to the CONSTANT_Utf8 constant pool items. This cache avoids multiple parsing of a given CONSTANT_Utf8 constant pool item.

    • constantDynamicValues

      private final ConstantDynamic[] constantDynamicValues
      The ConstantDynamic objects corresponding to the CONSTANT_Dynamic constant pool items. This cache avoids multiple parsing of a given CONSTANT_Dynamic constant pool item.

    • bootstrapMethodOffsets

      private final int[] bootstrapMethodOffsets
      The start offsets in classFileBuffer of each element of the bootstrap_methods array (in the BootstrapMethods attribute).
      另请参阅:

    • maxStringLength

      private final int maxStringLength
      A conservative estimate of the maximum length of the strings contained in the constant pool of the class.

  • 构造器详细资料

    • ClassReader

      public ClassReader(byte[] classFile)
      Constructs a new ClassReader object.
      参数:
      classFile - the JVMS ClassFile structure to be read.

    • ClassReader

      public ClassReader(byte[] classFileBuffer, int classFileOffset, int classFileLength)
      Constructs a new ClassReader object.
      参数:
      classFileBuffer - a byte array containing the JVMS ClassFile structure to be read.
      classFileOffset - the offset in byteBuffer of the first byte of the ClassFile to be read.
      classFileLength - the length in bytes of the ClassFile to be read.

    • ClassReader

      ClassReader(byte[] classFileBuffer, int classFileOffset, boolean checkClassVersion)
      Constructs a new ClassReader object. This internal constructor must not be exposed as a public API.
      参数:
      classFileBuffer - a byte array containing the JVMS ClassFile structure to be read.
      classFileOffset - the offset in byteBuffer of the first byte of the ClassFile to be read.
      checkClassVersion - whether to check the class version or not.

    • ClassReader

      public ClassReader(InputStream inputStream) throws IOException
      Constructs a new ClassReader object.
      参数:
      inputStream - an input stream of the JVMS ClassFile structure to be read. This input stream must contain nothing more than the ClassFile structure itself. It is read from its current position to its end.
      抛出:
      IOException - if a problem occurs during reading.

    • ClassReader

      public ClassReader(String className) throws IOException
      Constructs a new ClassReader object.
      参数:
      className - the fully qualified name of the class to be read. The ClassFile structure is retrieved with the current class loader's ClassLoader.getSystemResourceAsStream(java.lang.String).
      抛出:
      IOException - if an exception occurs during reading.

  • 方法详细资料

    • readStream

      private static byte[] readStream(InputStream inputStream, boolean close) throws IOException
      Reads the given input stream and returns its content as a byte array.
      参数:
      inputStream - an input stream.
      close - true to close the input stream after reading.
      返回:
      the content of the given input stream.
      抛出:
      IOException - if a problem occurs during reading.

    • calculateBufferSize

      private static int calculateBufferSize(InputStream inputStream) throws IOException
      抛出:
      IOException

    • getAccess

      public int getAccess()
      Returns the class's access flags (see Opcodes). This value may not reflect Deprecated and Synthetic flags when bytecode is before 1.5 and those flags are represented by attributes.
      返回:
      the class access flags.
      另请参阅:

    • getClassName

      public String getClassName()
      Returns the internal name of the class (see Type.getInternalName()).
      返回:
      the internal class name.
      另请参阅:

    • getSuperName

      public String getSuperName()
      Returns the internal of name of the super class (see Type.getInternalName()). For interfaces, the super class is Object.
      返回:
      the internal name of the super class, or null for Object class.
      另请参阅:

    • getInterfaces

      public String[] getInterfaces()
      Returns the internal names of the implemented interfaces (see Type.getInternalName()).
      返回:
      the internal names of the directly implemented interfaces. Inherited implemented interfaces are not returned.
      另请参阅:

    • accept

      public void accept(ClassVisitor classVisitor, int parsingOptions)
      Makes the given visitor visit the JVMS ClassFile structure passed to the constructor of this ClassReader.
      参数:
      classVisitor - the visitor that must visit this class.
      parsingOptions - the options to use to parse this class. One or more of SKIP_CODE, SKIP_DEBUG, SKIP_FRAMES or EXPAND_FRAMES.

    • accept

      public void accept(ClassVisitor classVisitor, Attribute[] attributePrototypes, int parsingOptions)
      Makes the given visitor visit the JVMS ClassFile structure passed to the constructor of this ClassReader.
      参数:
      classVisitor - the visitor that must visit this class.
      attributePrototypes - prototypes of the attributes that must be parsed during the visit of the class. Any attribute whose type is not equal to the type of one the prototypes will not be parsed: its byte array value will be passed unchanged to the ClassWriter. This may corrupt it if this value contains references to the constant pool, or has syntactic or semantic links with a class element that has been transformed by a class adapter between the reader and the writer.
      parsingOptions - the options to use to parse this class. One or more of SKIP_CODE, SKIP_DEBUG, SKIP_FRAMES or EXPAND_FRAMES.

    • readModuleAttributes

      private void readModuleAttributes(ClassVisitor classVisitor, Context context, int moduleOffset, int modulePackagesOffset, String moduleMainClass)
      Reads the Module, ModulePackages and ModuleMainClass attributes and visit them.
      参数:
      classVisitor - the current class visitor
      context - information about the class being parsed.
      moduleOffset - the offset of the Module attribute (excluding the attribute_info's attribute_name_index and attribute_length fields).
      modulePackagesOffset - the offset of the ModulePackages attribute (excluding the attribute_info's attribute_name_index and attribute_length fields), or 0.
      moduleMainClass - the string corresponding to the ModuleMainClass attribute, or null.

    • readRecordComponent

      private int readRecordComponent(ClassVisitor classVisitor, Context context, int recordComponentOffset)
      Reads a record component and visit it.
      参数:
      classVisitor - the current class visitor
      context - information about the class being parsed.
      recordComponentOffset - the offset of the current record component.
      返回:
      the offset of the first byte following the record component.

    • readField

      private int readField(ClassVisitor classVisitor, Context context, int fieldInfoOffset)
      Reads a JVMS field_info structure and makes the given visitor visit it.
      参数:
      classVisitor - the visitor that must visit the field.
      context - information about the class being parsed.
      fieldInfoOffset - the start offset of the field_info structure.
      返回:
      the offset of the first byte following the field_info structure.

    • readMethod

      private int readMethod(ClassVisitor classVisitor, Context context, int methodInfoOffset)
      Reads a JVMS method_info structure and makes the given visitor visit it.
      参数:
      classVisitor - the visitor that must visit the method.
      context - information about the class being parsed.
      methodInfoOffset - the start offset of the method_info structure.
      返回:
      the offset of the first byte following the method_info structure.

    • readCode

      private void readCode(MethodVisitor methodVisitor, Context context, int codeOffset)
      Reads a JVMS 'Code' attribute and makes the given visitor visit it.
      参数:
      methodVisitor - the visitor that must visit the Code attribute.
      context - information about the class being parsed.
      codeOffset - the start offset in classFileBuffer of the Code attribute, excluding its attribute_name_index and attribute_length fields.

    • readLabel

      protected Label readLabel(int bytecodeOffset, Label[] labels)
      Returns the label corresponding to the given bytecode offset. The default implementation of this method creates a label for the given offset if it has not been already created.
      参数:
      bytecodeOffset - a bytecode offset in a method.
      labels - the already created labels, indexed by their offset. If a label already exists for bytecodeOffset this method must not create a new one. Otherwise it must store the new label in this array.
      返回:
      a non null Label, which must be equal to labels[bytecodeOffset].

    • createLabel

      private Label createLabel(int bytecodeOffset, Label[] labels)
      Creates a label without the Label.FLAG_DEBUG_ONLY flag set, for the given bytecode offset. The label is created with a call to readLabel(int, cn.taketoday.bytecode.Label[]) and its Label.FLAG_DEBUG_ONLY flag is cleared.
      参数:
      bytecodeOffset - a bytecode offset in a method.
      labels - the already created labels, indexed by their offset.
      返回:
      a Label without the Label.FLAG_DEBUG_ONLY flag set.

    • createDebugLabel

      private void createDebugLabel(int bytecodeOffset, Label[] labels)
      Creates a label with the Label.FLAG_DEBUG_ONLY flag set, if there is no already existing label for the given bytecode offset (otherwise does nothing). The label is created with a call to readLabel(int, cn.taketoday.bytecode.Label[]).
      参数:
      bytecodeOffset - a bytecode offset in a method.
      labels - the already created labels, indexed by their offset.

    • readTypeAnnotations

      private int[] readTypeAnnotations(MethodVisitor methodVisitor, Context context, int runtimeTypeAnnotationsOffset, boolean visible)
      Parses a Runtime[In]VisibleTypeAnnotations attribute to find the offset of each type_annotation entry it contains, to find the corresponding labels, and to visit the try catch block annotations.
      参数:
      methodVisitor - the method visitor to be used to visit the try catch block annotations.
      context - information about the class being parsed.
      runtimeTypeAnnotationsOffset - the start offset of a Runtime[In]VisibleTypeAnnotations attribute, excluding the attribute_info's attribute_name_index and attribute_length fields.
      visible - true if the attribute to parse is a RuntimeVisibleTypeAnnotations attribute, false it is a RuntimeInvisibleTypeAnnotations attribute.
      返回:
      the start offset of each entry of the Runtime[In]VisibleTypeAnnotations_attribute's 'annotations' array field.

    • getTypeAnnotationBytecodeOffset

      private int getTypeAnnotationBytecodeOffset(int[] typeAnnotationOffsets, int typeAnnotationIndex)
      Returns the bytecode offset corresponding to the specified JVMS 'type_annotation' structure, or -1 if there is no such type_annotation of if it does not have a bytecode offset.
      参数:
      typeAnnotationOffsets - the offset of each 'type_annotation' entry in a Runtime[In]VisibleTypeAnnotations attribute, or null.
      typeAnnotationIndex - the index a 'type_annotation' entry in typeAnnotationOffsets.
      返回:
      bytecode offset corresponding to the specified JVMS 'type_annotation' structure, or -1 if there is no such type_annotation of if it does not have a bytecode offset.

    • readTypeAnnotationTarget

      private int readTypeAnnotationTarget(Context context, int typeAnnotationOffset)
      Parses the header of a JVMS type_annotation structure to extract its target_type, target_info and target_path (the result is stored in the given context), and returns the start offset of the rest of the type_annotation structure.
      参数:
      context - information about the class being parsed. This is where the extracted target_type and target_path must be stored.
      typeAnnotationOffset - the start offset of a type_annotation structure.
      返回:
      the start offset of the rest of the type_annotation structure.

    • readParameterAnnotations

      private void readParameterAnnotations(MethodVisitor methodVisitor, Context context, int runtimeParameterAnnotationsOffset, boolean visible)
      Reads a Runtime[In]VisibleParameterAnnotations attribute and makes the given visitor visit it.
      参数:
      methodVisitor - the visitor that must visit the parameter annotations.
      context - information about the class being parsed.
      runtimeParameterAnnotationsOffset - the start offset of a Runtime[In]VisibleParameterAnnotations attribute, excluding the attribute_info's attribute_name_index and attribute_length fields.
      visible - true if the attribute to parse is a RuntimeVisibleParameterAnnotations attribute, false it is a RuntimeInvisibleParameterAnnotations attribute.

    • readElementValues

      private int readElementValues(AnnotationVisitor annotationVisitor, int annotationOffset, boolean named, char[] charBuffer)
      Reads the element values of a JVMS 'annotation' structure and makes the given visitor visit them. This method can also be used to read the values of the JVMS 'array_value' field of an annotation's 'element_value'.
      参数:
      annotationVisitor - the visitor that must visit the values.
      annotationOffset - the start offset of an 'annotation' structure (excluding its type_index field) or of an 'array_value' structure.
      named - if the annotation values are named or not. This should be true to parse the values of a JVMS 'annotation' structure, and false to parse the JVMS 'array_value' of an annotation's element_value.
      charBuffer - the buffer used to read strings in the constant pool.
      返回:
      the end offset of the JVMS 'annotation' or 'array_value' structure.

    • readElementValue

      private int readElementValue(AnnotationVisitor annotationVisitor, int elementValueOffset, String elementName, char[] charBuffer)
      Reads a JVMS 'element_value' structure and makes the given visitor visit it.
      参数:
      annotationVisitor - the visitor that must visit the element_value structure.
      elementValueOffset - the start offset in classFileBuffer of the element_value structure to be read.
      elementName - the name of the element_value structure to be read, or null.
      charBuffer - the buffer used to read strings in the constant pool.
      返回:
      the end offset of the JVMS 'element_value' structure.

    • computeImplicitFrame

      private void computeImplicitFrame(Context context)
      Computes the implicit frame of the method currently being parsed (as defined in the given Context) and stores it in the given context.
      参数:
      context - information about the class being parsed.

    • readStackMapFrame

      private int readStackMapFrame(int stackMapFrameOffset, boolean compressed, boolean expand, Context context)
      Reads a JVMS 'stack_map_frame' structure and stores the result in the given Context object. This method can also be used to read a full_frame structure, excluding its frame_type field (this is used to parse the legacy StackMap attributes).
      参数:
      stackMapFrameOffset - the start offset in classFileBuffer of the stack_map_frame_value structure to be read, or the start offset of a full_frame structure (excluding its frame_type field).
      compressed - true to read a 'stack_map_frame' structure, false to read a 'full_frame' structure without its frame_type field.
      expand - if the stack map frame must be expanded. See EXPAND_FRAMES.
      context - where the parsed stack map frame must be stored.
      返回:
      the end offset of the JVMS 'stack_map_frame' or 'full_frame' structure.

    • readVerificationTypeInfo

      private int readVerificationTypeInfo(int verificationTypeInfoOffset, Object[] frame, int index, char[] charBuffer, Label[] labels)
      Reads a JVMS 'verification_type_info' structure and stores it at the given index in the given array.
      参数:
      verificationTypeInfoOffset - the start offset of the 'verification_type_info' structure to read.
      frame - the array where the parsed type must be stored.
      index - the index in 'frame' where the parsed type must be stored.
      charBuffer - the buffer used to read strings in the constant pool.
      labels - the labels of the method currently being parsed, indexed by their offset. If the parsed type is an ITEM_Uninitialized, a new label for the corresponding NEW instruction is stored in this array if it does not already exist.
      返回:
      the end offset of the JVMS 'verification_type_info' structure.

    • getFirstAttributeOffset

      final int getFirstAttributeOffset()
      Returns the offset in classFileBuffer of the first ClassFile's 'attributes' array field entry.
      返回:
      the offset in classFileBuffer of the first ClassFile's 'attributes' array field entry.

    • readBootstrapMethodsAttribute

      private int[] readBootstrapMethodsAttribute(int maxStringLength)
      Reads the BootstrapMethods attribute to compute the offset of each bootstrap method.
      参数:
      maxStringLength - a conservative estimate of the maximum length of the strings contained in the constant pool of the class.
      返回:
      the offsets of the bootstrap methods.

    • readAttribute

      private Attribute readAttribute(Attribute[] attributePrototypes, String type, int offset, int length, char[] charBuffer, int codeAttributeOffset, Label[] labels)
      Reads a non standard JVMS 'attribute' structure in classFileBuffer.
      参数:
      attributePrototypes - prototypes of the attributes that must be parsed during the visit of the class. Any attribute whose type is not equal to the type of one the prototypes will not be parsed: its byte array value will be passed unchanged to the ClassWriter.
      type - the type of the attribute.
      offset - the start offset of the JVMS 'attribute' structure in classFileBuffer. The 6 attribute header bytes (attribute_name_index and attribute_length) are not taken into account here.
      length - the length of the attribute's content (excluding the 6 attribute header bytes).
      charBuffer - the buffer to be used to read strings in the constant pool.
      codeAttributeOffset - the start offset of the enclosing Code attribute in classFileBuffer, or -1 if the attribute to be read is not a code attribute. The 6 attribute header bytes (attribute_name_index and attribute_length) are not taken into account here.
      labels - the labels of the method's code, or null if the attribute to be read is not a code attribute.
      返回:
      the attribute that has been read.

    • getItemCount

      public int getItemCount()
      Returns the number of entries in the class's constant pool table.
      返回:
      the number of entries in the class's constant pool table.

    • getItem

      public int getItem(int constantPoolEntryIndex)
      Returns the start offset in this ClassReader of a JVMS 'cp_info' structure (i.e. a constant pool entry), plus one. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      constantPoolEntryIndex - the index a constant pool entry in the class's constant pool table.
      返回:
      the start offset in this ClassReader of the corresponding JVMS 'cp_info' structure, plus one.

    • getMaxStringLength

      public int getMaxStringLength()
      Returns a conservative estimate of the maximum length of the strings contained in the class's constant pool table.
      返回:
      a conservative estimate of the maximum length of the strings contained in the class's constant pool table.

    • readByte

      public int readByte(int offset)
      Reads a byte value in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of the value to be read in this ClassReader.
      返回:
      the read value.

    • readUnsignedShort

      public int readUnsignedShort(int offset)
      Reads an unsigned short value in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start index of the value to be read in this ClassReader.
      返回:
      the read value.

    • readShort

      public short readShort(int offset)
      Reads a signed short value in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of the value to be read in this ClassReader.
      返回:
      the read value.

    • readInt

      public int readInt(int offset)
      Reads a signed int value in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of the value to be read in this ClassReader.
      返回:
      the read value.

    • readLong

      public long readLong(int offset)
      Reads a signed long value in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of the value to be read in this ClassReader.
      返回:
      the read value.

    • readUTF8

      public String readUTF8(int offset, char[] charBuffer)
      Reads a CONSTANT_Utf8 constant pool entry in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of an unsigned short value in this ClassReader, whose value is the index of a CONSTANT_Utf8 entry in the class's constant pool table.
      charBuffer - the buffer to be used to read the string. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the String corresponding to the specified CONSTANT_Utf8 entry.

    • readUtf

      final String readUtf(int constantPoolEntryIndex, char[] charBuffer)
      Reads a CONSTANT_Utf8 constant pool entry in classFileBuffer.
      参数:
      constantPoolEntryIndex - the index of a CONSTANT_Utf8 entry in the class's constant pool table.
      charBuffer - the buffer to be used to read the string. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the String corresponding to the specified CONSTANT_Utf8 entry.

    • readUtf

      private String readUtf(int utfOffset, int utfLength, char[] charBuffer)
      Reads an UTF8 string in classFileBuffer.
      参数:
      utfOffset - the start offset of the UTF8 string to be read.
      utfLength - the length of the UTF8 string to be read.
      charBuffer - the buffer to be used to read the string. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the String corresponding to the specified UTF8 string.

    • readStringish

      private String readStringish(int offset, char[] charBuffer)
      Reads a CONSTANT_Class, CONSTANT_String, CONSTANT_MethodType, CONSTANT_Module or CONSTANT_Package constant pool entry in classFileBuffer. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of an unsigned short value in classFileBuffer, whose value is the index of a CONSTANT_Class, CONSTANT_String, CONSTANT_MethodType, CONSTANT_Module or CONSTANT_Package entry in class's constant pool table.
      charBuffer - the buffer to be used to read the item. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the String corresponding to the specified constant pool entry.

    • readClass

      public String readClass(int offset, char[] charBuffer)
      Reads a CONSTANT_Class constant pool entry in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of an unsigned short value in this ClassReader, whose value is the index of a CONSTANT_Class entry in class's constant pool table.
      charBuffer - the buffer to be used to read the item. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the String corresponding to the specified CONSTANT_Class entry.

    • readModule

      public String readModule(int offset, char[] charBuffer)
      Reads a CONSTANT_Module constant pool entry in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of an unsigned short value in this ClassReader, whose value is the index of a CONSTANT_Module entry in class's constant pool table.
      charBuffer - the buffer to be used to read the item. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the String corresponding to the specified CONSTANT_Module entry.

    • readPackage

      public String readPackage(int offset, char[] charBuffer)
      Reads a CONSTANT_Package constant pool entry in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      offset - the start offset of an unsigned short value in this ClassReader, whose value is the index of a CONSTANT_Package entry in class's constant pool table.
      charBuffer - the buffer to be used to read the item. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the String corresponding to the specified CONSTANT_Package entry.

    • readConstantDynamic

      private ConstantDynamic readConstantDynamic(int constantPoolEntryIndex, char[] charBuffer)
      Reads a CONSTANT_Dynamic constant pool entry in classFileBuffer.
      参数:
      constantPoolEntryIndex - the index of a CONSTANT_Dynamic entry in the class's constant pool table.
      charBuffer - the buffer to be used to read the string. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the ConstantDynamic corresponding to the specified CONSTANT_Dynamic entry.

    • readConst

      public Object readConst(int constantPoolEntryIndex, char[] charBuffer)
      Reads a numeric or string constant pool entry in this ClassReader. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.
      参数:
      constantPoolEntryIndex - the index of a CONSTANT_Integer, CONSTANT_Float, CONSTANT_Long, CONSTANT_Double, CONSTANT_Class, CONSTANT_String, CONSTANT_MethodType, CONSTANT_MethodHandle or CONSTANT_Dynamic entry in the class's constant pool.
      charBuffer - the buffer to be used to read strings. This buffer must be sufficiently large. It is not automatically resized.
      返回:
      the Integer, Float, Long, Double, String, Type, Handle or ConstantDynamic corresponding to the specified constant pool entry.